Sodium Phosphate
Sodium phosphate is an osmotic laxative used for bowel cleansing before procedures like colonoscopy and for occasional constipation by drawing water into the colon.
Sodium phosphate is a laxative used for bowel cleansing before procedures and short-term constipation relief, working by drawing water into the intestines.
Key facts at a glance
- ATC
- A06AD17
- RxNorm
- 36709
- Generic
- Sodium Phosphate
- Class
- atc-a06
- Brands
- Aminosyn 8.5 % with Electrolytes, Sulfite-Free, Tis-U-Sol, OsmoPrep
- Availability
- rx
- Lactation
- unknown
- Routes
- oral
- Forms
- solution, tablet
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 500mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 250mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 400mg daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
10 groupspregnancy
first trimesteruse lowest effective dose
use only when benefits clearly outweigh potential risks
monitor fluid and electrolyte balance
Use with caution and monitor for adverse effects.
pregnancy
second trimesteruse lowest effective dose
use only when phosphate levels require supplementation
regular monitoring of phosphate and sodium levels
Use with caution and monitor for adverse effects.
pregnancy
third trimesteruse lowest effective dose
avoid high doses close to delivery
monitor fetal well-being and maternal electrolytes
Use with caution and monitor for adverse effects.
lactation
breastfeedingno adjustment needed
compatible with breastfeeding when used as directed
monitor infant for diarrhea or electrolyte changes
geriatric
elderlyreduce dose by 25-50%
use with caution due to reduced renal function and fluid balance sensitivity
frequent monitoring of renal function, electrolytes, and fluid status
Use with caution and monitor for adverse effects.
pediatric_age
children 2 12 yearsweight-based dosing required
use only under close medical supervision
monitor electrolytes closely including calcium and phosphate
Use with caution and monitor for adverse effects.
renal_impairment
mild to moderatereduce dose and monitor levels
use with caution and monitor phosphate levels frequently
regular monitoring of serum phosphate, calcium, and renal function
Use with caution and monitor for adverse effects.
renal_impairment
severeavoid use
contraindicated in severe renal impairment due to risk of phosphate accumulation
not applicable - avoid use
Use of this medication in this population requires careful consideration of risks and benefits.
hepatic_impairment
mild to moderateuse with caution
monitor liver function and electrolytes
monitor electrolytes and liver function tests
Use with caution and monitor for adverse effects.
alcohol_users
chronic alcohol usemonitor closely
alcohol users may have electrolyte imbalances requiring monitoring
monitor electrolytes including phosphate, magnesium, and potassium
Use with caution and monitor for adverse effects.
Statistics and clinical data
Drug class
Classification based on formulation (bowel cleanser vs parenteral nutrition)
Common uses
Primary therapeutic applications
FDA approval (OsmoPrep)
FDA approval year for sodium phosphate bowel cleanser
Mechanism of action
Pharmacological mechanism
Bowel preparation before colonoscopy, sigmoidoscopy, or other intestinal procedures; short-term treatment of occasional constipation; and relief of constipation associated with other conditions when softer stools are desired.
As an osmotic laxative, sodium phosphate draws water from the body into the colon through osmosis. This increased water content softens hard stool and increases intestinal bulk, stimulating natural bowel contractions and promoting evacuation.
Should not be used in patients with kidney disease, heart failure, or electrolyte imbalances. May cause dehydration and alter sodium, potassium, and phosphate levels. Avoid prolonged use beyond 1 week unless directed by a physician. Not recommended for children unless specifically prescribed. Older adults should use with caution due to increased risk of adverse effects.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
WellAlly may earn a referral fee from linked resources at no extra cost to you. Editorial content is never influenced by commercial relationships.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 24, 2026. · Read our editorial policy